✔ 最佳答案
(sin x -cos x) /(sec x - csc x)
= (sin x - cos x) /( 1/cos x - 1/ sin x) ------(1)
Consider (1/cos x - 1/sin x)
multiply and divide by sin x cos x
= (sin x - cos x) / sin x cos x
Equation (1) becomes:
(sin x - cos x) /[(sin x - cos x)] /sin x cos x]
= sin x cos x
= 2 sin x cos x / 2
= sin 2x / 2
Note;
Use parenthesis